System of refrigeration



June 23, 1925.

- Filed y 23, 1921' L. PENWELL SYSTEM OF REFRIGERATION 25 Sheets-Sheet 1June 23, 1925. i,543,27

L. PENWELL SYSTEM OF REFRIGERATION File July 23 1921 s Shets-Sheet 2 IL.PEINWELL SYSTEM OF REFRIGERATION File ly 23, 1921, S SheetS-Sh eet 5June '23, 1925. 1 1,543,027

Patented June 23, 1925.

UNITED STATES PATENT OFFICE.

LEWIS PENWELL, or

TION 00., or

CHICAGO, ILLINOIS, ASSIGNOR TO A.-B.-C. TRANSIT REFRIGERA- HELENA,MONTANA, A CORPORATION OF DELAWARE.

SYSTEM OF REFRIGERATION.

Application filed July 23, 1921. Serial Ne. 487,089.

To all whom it may] concern:

Be it known that I, LEWIS PENwnLL, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Systems ofRefrigeration, of which the following is a specification.

This invention relates broadly to heat ex- 19 change, particularly torefrigerating apparatus, and more specifically to such apparatus wherebythe cooling-is effected by circulation of a fluid heat-transfer mediumin association with the material which it 1 is desired to preserve. v

The general purpose of the present invention is the provision ofapparatus of the above specified sort which may be embodied in a smallinstallation suitable for use in retail shops and the like Where icecream or other commodities are dispensed, and which is adapted to beoperated effectively at small cost and with minimum power requirements.

Another object of the invention is the provision of such apparatus ofsuch simple nature as permits its being operated efficiently without anyspecial skill or technical knowledge on the part of the operator.

Another particular object of the invention is the provision of arefrigerating cabinet for preserving ice cream or similar commodities,and which is designed particularly to facilitating dispensing of thecommodities and to prevent contamination thereof by introduction offoreign material inadvertently into the dispensing containers.

Another particular object of the invention is the provision of suchapparatus designed to be cooled by ice, in which loss of coolingefiiciency from exposure of the ice to atmosphere is minimized.

Other and further objects of the invention will be pointed outhereinafter, indicated in the appended claims, or obvious upon anunderstanding of theinvention from the present disclosure.

In the drawings forming a part of this specification I have illustratedtwo forms in which the invention may be embodied, making said forms thebases of the present disclosure, but it is to be understood that thesame are submitted entirely for illustrative purposes and are not to beconstrued as limiting the invention hereinafter claimed short of itstrue and mose comprehensive scope in the art, as I am aware that it maybe embodied in other fashions.

In the drawings Fig.4 is a top view partly in section of the apparatusin the nature of an ice cream cabinet embodying my invention;

Fig. 2 is a top view of the circulating ap paratns in modified form;

Fig. 3 is a sectional elevation of the form illustrated in Fig. 1 takensubstantially on line 83 of said figure Fig. 4 is a transverse sectionalelevation through the cabinet and brine tank showing one form ofcirculating apparaus; and

Fig. 5 is a similar view showing the form of circulating apparatusillustrated in Figs. 1 and 3 and taken on substantially the line 55 ofthe former.

The invention will best be understood by reference to theseillustrations. Let it be understood that the numeral 1 designatesgenerally a cabinet forming an inclosure and housing for the appa ratusand the installation, said housing including a top portion 1 providedwith suitable openings with removable closures topermit introduction andremoval of containers and dispensing of material therefrom. Within thishousing are cooling and circulating means comprising a cooling tank 2and connected circulating columnar conduit 4.-. The cooling tank and thehousing above it are provided with openings joined by suitable thimble5, through which ice may be introduced into the tank, said openingsbeing closed by suitable heat insulated closures 6.- The circulatingconduit illustrated in Figs. 1 and 3 is in thenature of a thincontinuous tank- 'like member convoluted to provide receiving space forcylindrical containers 7 and to conformto their contour and affordintimate association. The space between the tank and circulating conduitand the 021s ing is filled with suitable heat insulated material. Thiscirculating conduit, excepting for the connections hereinaftermentioned,' is hermetically closed, and affords a continuous receptacleand circulating channel for the refrigerant. The ends of thiscirculatingconduit terminate adjacent the cooling tank and havecommunication therewith at two points, one of said points being at theinlet connection 8 and the other the outlet end thereof, but withoutaffording communication between. the cooling tank and the circulatingconduit in such portions of the latter. An intake pipe 11 leads from theinlet connection 8 tothe lower portion of the cooling tank, where itterminates at an open inlet end above the lower level of the outletconnection 9. The cooling tank is divided through part of its height bya partition 12 interposed between the intake end of the pipe 11 and theoutlet connection 9. Draw-oil connection 14 communicates with the lowerportion of the tank 2, and a vent connection 15 commu nicates with theupper portion of the circulating conduit.

On a bracket 16 supported on the top of the casing is mounted a smallmotor 17 which drives a pump shaft 18 housed in a tube 19 which projectsinto the tank 2. In

J the lower end of the tube 19 is carried a pump tube 20 into whichthepump shaft 18 is led through a packing gland 21. The

pump tube is open at its lower end and within it is a small impeller 22carried by the pump'shaft 18. The pump tube is arranged in thecompartment of the tank with which the outlet connection communicates,and discharges through an outlet 24 across the partition 12 into thecompartment of the tank with which the intake tube 11 communicates. Uponoperation of the motor 12 the impeller 22 is actuated to function as asmall rotary pump whichis effective to lift liquid from the outletcompartment into the inlet compartment of the tank and to maintain adifference of level of liquid in the two.

In the operation of the preferred embodis ment of the cabinet, ice andsalt are introduced to the tank 2 with a sufiicient quantity of water toproduce a volume of brine adequate to fill the system. An air pump isconnected to the vent 15 and suction created thereby to draw the brineinto the circulating conduit 4-. The action of the air pump is continueduntil the conduit 4 is completely filled, which is indicated by theappearance of the brine at the air pump. Obviously as the brine is drawninto the circulating system the level of the same falls in the coolingtank 2, but enough must be retained therein to keep a considerableportion of the pipe 11 immersed. At this stage,

aseaoaa however, the level in the compartments of the tank may be thesame and until a differential level is created no circulation of thebrine occurs. But this differential is established by operation of themotor 17 and the impeller 22 which lowers the head in the outlet tankand increases the head in the inlet tank. Whereupona syphonic orequalizing flow is induced in the circulating system, which tends toequalize the head in the two compartments-and which consequentlycontinues until the level of the brine in the outlet compartment'reachesthe level of that in the inlet compartment. At this time the pump againisstarted to create the differential level or pressure and the syphonicor equalizing circulation again results. The cold brine is drawn throughthe intake pipe 11 into the upper portion of the inlet end of thecirculating conduit, and being colder than the brine in the conduit,tends to lower and equalize the temperature throughout the height of thelatter in the course of its circulation longitudinally as well asvertically in the same. This will result in the maintenance ofsubstantially uniform temperature throughout the height of thecirculating conduit with the result that the material in the containerswill be maintained at substantially uniform temperature throughout itsentire depth. While the brine at the discharge end of the con duit willbe warmer than that at the inlet end, thiswill not have an undesirableeffect upon the material in the cause of the fact that the containersubjected to the influence of the warmest brine is also subjected to theinfluence of the coldest brine. Ihe cross connection pipe 10 forms achannel through which brine may circulate from one end of the conduit tothe other end thereof. being subjected in its passage to theinfluence'of the ice in the tank.

As an alternative to the foregoing the application of the air pump tothe vent 15 may be eliminated by supplying a sufficient quantity ofbrine to the tank 2 to fill the circulating conduit by gravity, leavingthe valve of the pipe 15 open to permit escape of the air from thecirculating system, then closing said valve and drawing oft" enough.containers, be-

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of the brine from the tank to reduce the above the level of the brine inthe outlet tank 2 to an effective level cold brine to enter thecirculating compart: ment 4 to take the place of the relatively warmbrine which has passed out from that compartment into the outletcompartment of the tank 2, which circulation occurs also during the timethe pump 22 is operated. With the re-establishment of correspondinglevels ofbrine in the two compartments of the cooling tank thecirculation of the brine in the circulating compartment ceases, the coldbody. of brine in that'compa'rtment serves to preserve in a coolcondition the contents of the containers 7.

In ordinary circumstances the operation of the pump isetfected'approxiinately every fifteen minutes, and the pump operates fora period of approximately one minute. This has been found sufficient toimpart circulation to the brine so as to withdraw the relatively warmportion thereof from the circulating compartment land to force into saidcompartment a sufiicient quantity of the cold brine to take the place ofthe relatively warm brine Whichdias been withdrawn.- However theoperation of the pump may be automatically effected by a thermostaticswitch or through time mechanism which will give to the circulation ofthe brine the periodic impulses above referred In the absence of theautomatic control the starting and stoppingof the motor, operation of ahand switch at suitable periods will be resorted to for effecting thischange of the brine.

The circulation described is intended to. reach the conditions wherethecabinet is in operation through the day, and repeated opening of thesame for'access to the contents of the containers exposes the conduit tothe atmospheric temperature, thus requiring cooling of the brine morefrequently than where the cabinet remains closed for acontinued period,such as at nighttime. In the latter condition, the compartment 4 may beheld at the proper temperature, due to the fact that atmospherictemperature does not modify'to any appreciable extent the temperature ofthe brine in the compartment, and in this condition of the apparatus thebrine will remain sufliciently cold for a period of eight or ten hourswithout circulation, such as is required in day time service.

Apparatus constructed and operated in this fashion will maintain acontinuous and uniform circulation of the cooling medium and maintainthe material in the containers at the desired temperature so long as iceis kept in the tank. As the circulating medium becomes diluted throughmelting of the 'ice, a proper amount may be drawn off through theconnection 14 and a proper amount of salt or concentrated brine solutionadded to bring that in thetank and conduit up to the desired strength. a

In the modification illustrated in Fig. 2 the circulating conduit is notconvoluted, but is shaped in suitable form to-encompass the containersof rectangular or other form. In Fig. 4 is shown a modified form of thebrine circulating means. In this form the tank is not divided into thetwo compartments for maintaining different levels of liquid, but thecirculation is induced by the pumping of the brine from the tankdirectly into the inlet connection 8, the rotary pump operating Withinthe intake pipe 11*.

' WVhen designed as a dispensing cabinet, as for ice cream, theinvention affords a particularly economical and sanitary installation.The ice is not exposed to the atmosphere incident to the opening of thecabinet for removal of the material, nor is it necessary to keep thecontainers in ice or water, as they are now customarily; cooled, and thelikelihood of such materials finding entrance into the containers isthereby obviated. I

The arrangement furthermore preserves the containers in whichthematerial is kept, as they are not subjected to contact of the brineas in cases where the containers are packed directly in salted ice.Interchange of the containers is facilitated, as there is nothing tointerfere with their insertion into the receiving space of thecirculation jacket and their removal therefrom.

I claim:

1.'A refrigerating apparatus comprising the combination of an insulatingreceptacle, an enclosed casing located therein providing a columnarpassageway, a refrigerant supply vessel located in the insulatingreceptacle and communicating with said passage-way,

and means for causing a How of the refrigerant through said passage-wayand the refrigerant supply vessel.

2. A refrigerating apparatus comprisin the combination of a receptacle,an enclose casing located therein providing a columnar passage way, arefrigerant supply vessel 10- tank whereby a syphonic circulation can Ioccur through the columnar conduit and the brine tank, and means forinducing the syphonic circulation.

4. A refrigerating apparatus comprising an outer receptacle, arefrigerant supply tank located therein, a columnar conduit 10- cated inthe outer receptacle and communicating with said refrigerant supplytank, and a conduit between different levels of the columnar conduitpassing through the refrigerant supply vessel whereby heat exchange andcirculation of the refrigerant medium is induced.

5. A refrigerating apparatus comprising an outer receptacle, arefrigerant receptacle therein, a columnariconduit communicating withsaid refrigerant receptacle, said refrigerant receptacle and thecolumnar-conduit located wholly within and spaced an appreciably widedistance from the side walls of the outer receptacle, insulatingmaterial filling said space, and a conduit between difl'erent levels ofthe columnar consduit passing through the refrigerant supply vesselwhereby heat exchange and circulation of the refrigerant medium isinduced.

6. In a refrigerating apparatus, the combination with a container of acirculating conduit affording a path for the circulation of liquid aboutthe container, a brine tank adapted to retain a supply of liquid at alower level than that in the circulating conduit, said brine tank socommunicating with the respective terminals of the circulating conduitthat a syphonic circulation can occur through the conduit and the brinetank, and means associated with the tank for inducing the syphoniccirculation.

7 In arefrigerating apparatus, the combi ment at a higher level thanthat in the discompartment.

charge 8. n a refrigerating apparatus, the combination with a container,of a conduit for circulating liquid in association with said container,a supply compartment having communication with the upper portion of oneterminal of said conduit, a, discharge compartment having communicationwith the lower portion of the other terminal of said conduit, saidconduit and compartments being arranged to retain liquid in the formerat a higher level than in the latter, and means for maintaining liquidin one of said compartments at a higher level than in the othercompartment.

' In testimony whereof I have hereunto subscribed my name.

LEWIS PEN WELL.

